The connections on a PCB should be identical to its corresponding circuit diagram, but while the circuit diagram is arranged to be readable, the PCB layout is arranged to be functional, so there is rarely any visible correlation.

A lot of identifications contribute to the wide use of Printed Circuit Boards (PCBs), including electronic components, platforms for electronic parts, and electronic connection providers. According to the number of layers, PCBs can be classified into the following three categories: single, double and multilayer PCBs. Ordinarily, multilayer PCBs have 4 or 6 layers and some complicated multilayer PCBs have more.munity.